Analysis: KTM Duke 390 Alloy wheel cracking problem

This is a discussion on Analysis: KTM Duke 390 Alloy wheel cracking problem within Ride Safe, part of the Road Safety category; Originally Posted by PratikPatel
Looks more like a metallurgy or a process problem. I have a set of similar style ...

Looks more like a metallurgy or a process problem. I have a set of similar style rims by Brembo on my Ninja 300. These are forged and extremely light weight. The rims are so optimised for weight that they have a hollow centre hub to reduce weight. These rims are extremely tough and durable.

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Out of curiosity , are the rims on your ninja stock or aftermarket , if aftermarket then do you reckon the same can be used on ktm 390 and what is the expected damage ?

Looks more like a metallurgy or a process problem. I have a set of similar style rims by Brembo on my Ninja 300. These are forged and extremely light weight. The rims are so optimised for weight that they have a hollow centre hub to reduce weight. These rims are extremely tough and durable.

Please post some pics and details of your rims including cost. I'm hoping that the third party players bring out some light, yet good quality wheels once the RC 390 comes out. If that happens, the Duke owners can use them too. They may cost a bomb, but the peace of mind offered would be worth the price.

Out of curiosity , are the rims on your ninja stock or aftermarket , if aftermarket then do you reckon the same can be used on ktm 390 and what is the expected damage ?

Yes, these can be used with the 390. In fact I have a additional set of rims that I have kept aside for the RC 390 that I am planning to get in near future. The listed price in U.K. is about 900 Euros.

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Originally Posted by theredliner

Please post some pics and details of your rims including cost. I'm hoping that the third party players bring out some light, yet good quality wheels once the RC 390 comes out. If that happens, the Duke owners can use them too. They may cost a bomb, but the peace of mind offered would be worth the price.

The good thing about the KTM rims are that they are of standard international size. Therefore if you wish to opt for aftermarket ones, a number of options are available such as Dymag, Marchesini, Marvic, etc. However, this is a very expensive proposition. There was nothing wrong with my stock set of rims. I was looking ways to increase the performance of the bike and one of the areas identified was reducing wheel weight and mass. We were able to reduce the weight by 5.5 kgs from spinning mass due to this change. Which translates directly into more useable power at the rear wheel.

.....I was looking ways to increase the performance of the bike and one of the areas identified was reducing wheel weight and mass. We were able to reduce the weight by 5.5 kgs from spinning mass due to this change. Which translates directly into more useable power at the rear wheel.

Hey Pratik. I have seen the thread regarding the ninja 'Sans' in xBhp. Are you the same person?

Anyways. That is one well prepped 300.

BTW. How can this alloy accomodate the 390's disc rotor which is mounted on the left side?

I guess that this might not be a mystery at all but a simple lack of good QC on part of Bajaj. It could be that the quality control has not been stringent enough and it is showing up randomly among buyers. Because we have lots of Indian KTM owners all congregating in a handful of forums we get to know more about wheel breakage here than those in exported ones. Or it could be a design issue and that they wanted the wheel to be as light as the spec allowed to reduce overall weight of the bike but this causes problems in Indian conditions.

I have a 7 year old Honda Unicorn limited edition which came with orange powder coated alloy wheels from company. I ride the bike hard and show little mercy for humps and potholes but have faced no problem so far, it's touch wood.

The rims are sourced from China I've heard , they are all cast items. The 200's rims are powder coated too (black).

I spoke to the KTM Marthahalli showroom folks on D390 rims today and they confirmed that the rims are manufactured in the Bajaj plant in Pune. The RC390 has alloys that are heavier and have been tested to take a fair bit of punishment on our roads. As reported by fellow members, these alloys are being shared with the D390 which has now increased in weight.

The RC390 has alloys that are heavier and have been tested to take a fair bit of punishment on our roads. As reported by fellow members, these alloys are being shared with the D390 which has now increased in weight.

Is'nt there any other way to make the alloy stronger instead of increasing its weight as well as the unsprung mass?

I have a 7 year old Honda Unicorn limited edition which came with orange powder coated alloy wheels from company. I ride the bike hard and show little mercy for humps and potholes but have faced no problem so far, it's touch wood.

Your 7 year old Unicorn has a wheel which is less wider than the Duke,s. The wider the tire less structurally sound it is going to be along the rim (lip) because the spokes join into the rim at the center only. Whatever is extending away from the spoke is not as structurally strong as it would be on a rim which is comparatively less wider. The guy who made this video a few posts ago is really talking sense. Its not that the wheels cracked when the bike was standing still.

Your 7 year old Unicorn has a wheel which is less wider than the Duke,s. The wider the tire less structurally sound it is going to be along the rim (lip) because the spokes join into the rim at the center only. Whatever is extending away from the spoke is not as structurally strong as it would be on a rim which is comparatively less wider. The guy who made this video a few posts ago is really talking sense. Its not that the wheels cracked when the bike was standing still.

Going by that logic, why are we not hearing much about the rim crack in FZ-16 which has one of the lowest profile/tire height.

There are a lot of reasons and I do not know why people are making a fuss about it. Of course you can get killed if your rim breaks, but the same can happen if you get off balance in a pothole. Potholes are a menace in general. Just ride carefully and claim insurance for a new set of wheels to replace the old ones.

There are a lot of reasons and I do not know why people are making a fuss about it. Of course you can get killed if your rim breaks, but the same can happen if you get off balance in a pothole. Potholes are a menace in general. Just ride carefully and claim insurance for a new set of wheels to replace the old ones.

I cannot believe you are saying this!

Why are we making a fuss because rims are cracking, imploding, splitting open like eggshells?

Which other biike in India currently have you heard such a fuss about this issue on?

So are you saying all the guys making a fuss about this are overreacting and don't know what they are talking about?

That's got to be the mother of all sweeping statements.

Its not always possible to spot a pothole in time to either brake or go around it. And it impractical to always be riding at a speed that if you do hit a pothole, damagel will not ensue. If you had to ride like that, you would not be buying a Duke (any Duke) in the first place.

So if the manufacture is making a bike like the Duke, and selling it for profit, then he is RESPONSIBLE for providing it with wheels that do not give way like this. Responsible AND LIABLE.

Tomorrow would you say the same thing if the Dukes came with crappy brakes that could not stop the bike in time, or would fail above a certain speed or under a specific set of circumstances? Would your reaction be the same - i.e. why the hell are we making a big song and dance about the bike not stopping? Of course the bike not stopping means the rider could get killed. So what? A rider can get killed if he goes too fast and headon into an oncoming truck as well. After all, trucks are a menace in general. So lets just ride carefully. And hope when we do crash into the oncoming truck, because of the crappy brakes, we don't die. Simply claim insurance for the bike that in all likelihood would be totalled, and get a new bike to replace it. IF you are not permanently disabled by then and can still ride. If you cannot, or are dead, well then you and/or the family can always claim disability or accidental death benefits.

So are you saying all the guys making a fuss about this are overreacting and don't know what they are talking about?

This is exactly what you are implying.

On the other hand people are not happy with the replacement wheels which are heavier... what do you think I have to say to that?

It must be noted that the number of cases of pinch damage in low profile tires on cars is much more than the Duke rim cracks (totally as per my knowledge, I have not stats) but since you are in a car you are safer and the gory imagination of eventualities is kept on curb... being on a bike is the first sin you do... and whatever events you said would entail in case of a head on collision with a truck is exactly how the courts would look at it... there should be no hard feelings.

If you are saying that KTM should recall the bikes, submit an apology, compensate the people who have suffered due to this potentially fatal failure, I totally stand by you.

On the other hand people are not happy with the replacement wheels which are heavier... what do you think I have to say to that?

That has been discussed here. Its the cheap and not very scientific fix, which requires little R&D. There are other ways of making the wheels stronger besides throwing extra material into it. Forged wheels, internal metallurgical matrix construct, strengthening weak points by providing properly positioned support, all of this can and has ben done. A heavier wheel is the typical China mag alloy solution - which these wheels are, incidentally.

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It must be noted that the number of cases of pinch damage in low profile tires on cars is much more than the Duke rim cracks (totally as per my knowledge, I have not stats) but since you are in a car you are safer and the gory imagination of eventualities is kept on curb... being on a bike is the first sin you do... and whatever events you said would entail in case of a head on collision with a truck is exactly how the courts would look at it... there should be no hard feelings.

Are you saying insurance companies do not cover bike riders? Are you also saying that bike manifacturers can get away with dangerous equipment and quality because the risks inherent to motorcycling are greater than driving cars? Should it not be the reverse? So that they bring the odds back into the rider's favor to the extent possible?

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If you are saying that KTM should recall the bikes, submit an apology, compensate the people who have suffered due to this potentially fatal failure, I totally stand by you.

KTM needs to find a solution first. The rest comes later. A sorry and compensation or replacment of faulty equipment is zero consolation to any rider who trusts his machine with his life - especially at the speeds the 390 is capable of doing.

If your wheels cannot take the speeds the bike can do, detune the engine to speeds you can assure riders the wheels can handle. Or give the machine the wheels it needs. There is no middle path.

The current path of replacement and statistics is not a path. Not a solution. It is temporary deflection. Hopefully it should buy them the time they need to find an answer.